You are right a Colon Cleanse is the next step- after having started taking standard suppl. (you did not mention so I want to make sure: magnesium or butyric acid, vitamin B complex and selenium.)
Oxypowder is a good Bowel Cleanse BUT because candida drills into the intestinal walls and is holding there you will not expell any with that cleanse. But still, you will perform a good Bowel Cleanse without getting candida threads out. Psyllium will otherwise help the threads out (P & B shakes will too AND will absorb toxins and thus limit damages to your bowels- it is a different protocole - if you choose this one write again and I will give you the details). I am no expert in Oxygen - some posts here used to say it was helpful, but I hve never tried it.
Probiotics. IF you do Oxy-clease or P & B shakes introduce them after the cleanse. If you do only psyllium take them along. Opinions differ on the best probiotics. Mine is that home made kefir is the very best followed by home made yogurt - followed by supplements.
HOw to tell one is cured is a good question. I would recommend
A-the bowel cleanse
B- the parasite cleanse
C the kidney cleanse
D the liver cleanse
as a complete protocole BEFORE testing out.
THe BEST way to tell remains to see how you react after eating sugar.